1. Field of the Invention
This invention relates to dewaxing of petroleum distillates thereby producing an upgraded feed and a C.sub.3 -C.sub.4 olefin product fraction. This invention deals with hydrodewaxing a distillate feed using a ZSM-5-type zeolite catalyst. More particularly, it relates to dewaxing a distillate feed and producing C.sub.3 -C.sub.4 olefins by contacting the feed with a ZSM-5-type catalyst under low-pressure conditions.
2. Description of the Prior Art
Dewaxing of virgin petroleum distillates using a ZSM-5 catalyst is known in the art (see, for example, U.S. Pat. Nos. 3,894,939--W. E. Garwood--and 4,067,797--N.Y. Chen et al). However, these known processes suffer from disadvantages, including (1) high catalyst fouling or deactivating rates and (2) little or none of the C.sub.3 -C.sub.4 product fraction is C.sub.3 -C.sub.4 olefins.
It is an object of this invention to provide a novel process for carrying out catalytic upgrading of a petroleum distillate in a more effective manner.
It is an object of this invention to provide a process in which at least a substantial portion of the product produced by catalytically dewaxing a distillate using a ZSM-5-type zeolite is a C.sub.3 -C.sub.4 olefin fraction.
Other and additional objects of this invention will be clear from a consideration of the complete specification including the claims thereof.